1. Field of the Invention
The field of the present invention relates to a telephone guard or lock.
2. Description of the Prior Art
A plurality of telephone locks or guards are known, the purpose of which is to prevent a user from making unauthorized calls.
For example there is known a telephone security device which is intended to prevent unauthorized use of the distant-direct-dialing facility on dial type telephones. It makes use of a mechanism which is stepped by operation of the dial to call a digit, and which after a predetermined number of digits has been called, locks the dialing mechanism to prevent further dialing. The predetermined number is so selected as to prevent the desired misuse of the telephone. There is also known an apparatus for preventing the dialing of toll call telephone numbers using a public utility rotary dial telephone. The latter apparatus permits local telephone calls to be completed and can be disabled to permit toll calls by a key operated assembly. The apparatus can also be converted into a local call pay telephone. There is additionally known a telephone long distance attachment for attaching to a standard telephone on the outside housing thereof, without in any way dismantling the telephone, for preventing long distance calls and at the same time facilitating local calls in which a first ratchet mechanism limits the number of dialed digits to those required for a local call only, a second ratchet mechanism prevents dialing the operator on the first dial, and a third ratchet mechanism prevents the release of the telephone buttons before they are fully pressed to prevent dialing by depressing the buttons. There is further known a pay phone for local calls only which has a counter mechanism associated with the dial to sense prohibited digits (e.g., "1" or "0") in specific positions within a telephone number and to disable the phone when a toll call is attempted; a key operated switch overrides the disabling circuit to permit key-holders to make unlimited calls.